Olefinic thermoplastic elastomer, process for production thereof, olefinic thermoplastic elastomer compositions, process for producing the same, and moldings thereof

ABSTRACT

An olefin thermoplastic elastomer containing an olefin random copolymer formed by copolymerizing ethylene, an alpha-olefin having 3 to 10 carbon atoms and an unsaturated monomer having a functional group, and optionally a non-conjugated diene, and metal ions crosslinking the olefin random copolymer, has the same or similar rubber elasticity, flexibility and molding and processability as the conventional olefin thermoplastic elastomers, and has good mechanical properties, wear resistance, in particular scratch resistance.

TECHNICAL FIELD

The present invention relates to an olefin thermoplastic elastomer and aproduction process thereof, an olefin thermoplastic elastomercomposition and a production process thereof, and molded products, andmore particularly to an olefin thermoplastic elastomer excellent inrubber elasticity, flexibility, mechanical properties, scratchresistance, wear resistance, molding or forming and processability, heatresistance and weather resistance and a production process thereof, anolefin thermoplastic elastomer composition and a production processthereof, and molded or formed products.

BACKGROUND ART

Those obtained by mixing an olefin resin with an olefin copolymerrubber, those obtained by partially crosslinking an olefin resin and anolefin copolymer rubber with a crosslinking agent, etc. have heretoforebeen known as olefin thermoplastic elastomers. Such olefin thermoplasticelastomers attract attention, in fields of automotive parts and the likein particular, as substitutive materials for metal parts with the mainpurpose of lightening the weight, substitutive materials for RIMurethane parts with the main purpose of improving part's life andreducing cost, substitutive materials for vulcanized rubber with themain purpose of simplifying processing steps, improving recyclingability and reducing cost, substitutive materials for soft polyvinylchloride with the main purpose of improving part's life and protecting aglobal environment, or the like because they are excellent in heatresistance, weather resistance, cold resistance and molding or formingand processability and comparatively cheap materials, and demand for theolefin thermoplastic elastomers increase year by year.

Since the conventional olefin thermoplastic elastomers are low inresistance to surface scratching (scratch resistance), however, theelastomers involve a problem that they are unsuitable for use as surfacematerials for molded or formed products of which the scratch resistanceis required, for example, inner panels, console boxes or the like.

DISCLOSURE OF THE INVENTION

The present invention has been made on the basis of the foregoingcircumstances and has as its object the provision of an olefinthermoplastic elastomer having the same or similar rubber elasticity,flexibility and molding or forming and processability as those of theconventional olefin thermoplastic elastomers, and are good in mechanicalproperties and wear resistance and excellent in scratch resistance inparticular and a production process thereof, a composition containingthe olefin thermoplastic elastomer and a production process thereof, andmolded or formed products thereof.

According to the present invention, there is thus provided an olefinthermoplastic elastomer comprising an olefin random copolymer formed bycopolymerizing ethylene, an α-olefin having 3 to 10 carbon atoms and anunsaturated monomer having a functional group, and optionally anon-conjugated diene, and metal ions crosslinking the olefin randomcopolymer.

In the olefin thermoplastic elastomer according to the presentinvention, the functional group in the unsaturated monomer having afunctional group may preferably be a carboxyl group, hydroxyl group,epoxy group or sulfonic group.

In the olefin thermoplastic elastomer according to the presentinvention, the unsaturated monomer having a functional group maypreferably be a functional cyclic compound represented by the followinggeneral formula (1):

wherein R¹ means a hydrogen atom or a hydrocarbon group having 1 to 10carbon atoms, Y¹, Y² and Y³ denote, independently of one another, ahydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms or —COOH,with the proviso that at least one of Y¹, Y² and Y³ is —COOH, and whenat least two of Y¹, Y² and Y³ are —COOH, they may be bonded to eachother to form an acid anhydride (—CO—(O)—CO—), o is an integer of 0 to2, and p is an integer of 0 to 5.

In the olefin thermoplastic elastomer according to the presentinvention, the olefin random copolymer may preferably be formed bycopolymerizing 35 to 94.99 mol % of ethylene, 5 to 50 mol % of theα-olefin having 3 to 10 carbon atoms, 0.01 to 5 mol % of the functionalcyclic compound represented by the general formula (1) and 0 to 10 mol %of the non-conjugated diene.

In the olefin thermoplastic elastomer according to the presentinvention, the metal ions may preferably be ions of a metal selectedfrom the group consisting of potassium, sodium, aluminum, magnesium,barium, zinc, iron, calcium, titanium and lead.

The olefin thermoplastic elastomer according to the present inventionmay preferably have a melt flow rate of at least 0.5 g/10 min asmeasured under conditions of a temperature of 230° C. and a load of 10kg, a permanent set of at most 30% and a durometer A hardness of at most96.

According to the present invention, there is also provided a process forproducing an olefin thermoplastic elastomer, which comprises the step ofmixing a solution with 100 parts by weight of an olefin random copolymerformed by copolymerizing 35 to 94.99 mol % of ethylene, 5 to 50 mol % ofan α-olefin having 3 to 10 carbon atoms, 0.01 to 5 mol % of a functionalcyclic compound represented by the general formula (1) and 0 to 10 mol %of a non-conjugated diene dissolved in a solvent with a liquid with 0.1to 20 parts by weight of a metal compound dissolved or dispersed in asolvent, at a temperature of at least 20° C. and the step of removingthe solvent(s) from the resultant liquid mixture.

According to the present invention, there is further provided a processfor producing an olefin thermoplastic elastomer, which comprises thestep of subjecting 100 parts by weight of an olefin random copolymerformed by copolymerizing 35 to 94.99 mol % of ethylene, 5 to 50 mol % ofan α-olefin having 3 to 10 carbon atoms, 0.01 to 5 mol % of a functionalcyclic compound represented by the general formula (1) and 0 to 10 mol %of a non-conjugated diene and 0.1 to 20 parts by weight of a metalcompound to a dynamic heat treatment under conditions of a temperatureof 120 to 350° C. and a shear rate of 10 to 2,000 s⁻¹.

According to the present invention, there is still further provided anolefin thermoplastic elastomer composition comprising the olefinthermoplastic elastomer described above, and a polymeric compoundselected from a thermoplastic resin and rubber and/or a softening agent,wherein

the polymeric compound and the softening agent are contained inproportions of at most 300 parts by weight and at most 100 parts byweight, respectively, per 100 parts by weight of the olefin randomcopolymer forming the olefin thermoplastic elastomer.

The olefin thermoplastic elastomer composition according to the presentinvention may preferably have a melt flow rate of at least 0.5 g/10 minas measured under conditions of a temperature of 230° C. and a load of10 kg, a permanent set of at most 30% and a durometer A hardness of atmost 96.

According to the present invention, there is yet still further provideda process for producing an olefin thermoplastic elastomer composition,which comprises the step of subjecting 100 parts by weight of an olefinrandom copolymer formed by copolymerizing 35 to 94.99 mol % of ethylene,5 to 50 mol % of an α-olefin having 3 to 10 carbon atoms, 0.01 to 5 mol% of a functional cyclic compound represented by the general formula (1)and 0 to 10 mol % of a non-conjugated diene, 0.1 to 20 parts by weightof a metal compound, and at most 300 parts by weight of a polymericcompound selected from a thermoplastic resin and rubber and/or at most100 parts by weight of a softening agent to a dynamic heat treatmentunder conditions of a temperature of 120 to 350° C. and a shear rate of10 to 2,000 s⁻¹.

According to the present invention, there is yet still further provideda molded or formed product formed of the olefin thermoplastic elastomeror olefin thermoplastic elastomer composition described above.

BEST MODE FOR CARRYING OUT THE INVENTION

The embodiments of the present invention will hereinafter be describedin detail.

The olefin thermoplastic elastomer according to the present inventioncomprises an olefin random copolymer (hereinafter referred to as“specific functional group-containing copolymer”) formed bycopolymerizing at least ethylene, an α-olefin having 3 to 10 carbonatoms and a compound having a functional group, and metal ionscrosslinking the specific functional group-containing copolymer.

[Specific Functional Group-Containing Copolymer]

In the specific functional group-containing copolymer making up theolefin thermoplastic elastomer according to the present invention,ethylene is used as an essential monomer component.

The proportion of ethylene used is preferably 35 to 94.99 mol %, morepreferably 40 to 89.99 mol %, particularly preferably 45 to 84.99 mol %based on the whole monomer component.

If the proportion of ethylene used is lower than 35 mol %, it may bedifficult in some cases to copolymerize a functional cyclic compound,which will be described subsequently. If the proportion of ethylene usedexceeds 94.99 mol % on the other hand, it may be difficult in some casesto achieve rubber elasticity required in the resulting thermoplasticelastomer.

In the specific functional group-containing copolymer, an α-olefin(hereinafter referred to as “specific α-olefin”) having 3 to 10 carbonatoms is used as an essential monomer. When the α-olefin having at most10 carbon atoms is used, the copolymerizability of such an α-olefin withother monomers becomes satisfactory.

As specific examples of the specific α-olefin, may be mentionedpropylene, 1-butene, 1-pentene, 4-methyl-pentene-1,1-hexene, 1-heptene,1-octene and 1-decene. Among these, propylene, 1-butene, 1-hexene and1-octene are preferred, with propylene and 1-butene being morepreferred.

These compounds may be used either alone or in any combination thereof.

The proportion of the specific α-olefin used is preferably 5 to 50 mol%, more preferably 10 to 45 mol %, particularly preferably 15 to 40 mol% based on the whole monomer component.

If the proportion of the specific α-olefin used is lower than 5 mol %,it may be difficult in some cases to achieve rubber elasticity requiredin the resulting thermoplastic elastomer. If the proportion of ethyleneused exceeds 50 mol % on the other hand, the durability of the resultingelastomer may be deteriorated in some cases.

In the specific functional group-containing copolymer, an unsaturatedmonomer (hereinafter referred to as “functional group-containingunsaturated monomer”) having a functional group which can be crosslinkedwith metal ions is used as an essential monomer. This functionalgroup-containing unsaturated monomer preferably has a carboxyl group,hydroxyl group, epoxy group or sulfonic group as a functional group.

As such a functional group-containing unsaturated monomer, is preferablyused a functional cyclic compound (hereinafter referred to as “specificfunctional cyclic compound”) represented by the above general formula(1).

In the general formula (1) representing the specific functional cycliccompound, R¹ is a hydrogen atom or a hydrocarbon group having 1 to 10carbon atoms, Y¹, Y² and Y³ are, independently of one another, ahydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms or —COOH,with the proviso that at least one of Y¹, Y² and Y³ is —COOH. When atleast two of Y¹, Y² and Y³ are —COOH, they may be bonded to each otherto form an acid anhydride (—CO—(O)—CO—).

As specific examples of the hydrocarbon group having 1 to 10 carbonatoms, may be mentioned methyl, ethyl, propyl, butyl, pentyl, hexyl,heptyl, octyl, nonyl and decyl groups.

The number o of repetition is an integer of 0 to 2. If the number o ofrepetition is 3 or more, it may be difficult in some cases tocopolymerize such a cyclic compound with other monomers. The number p ofrepetition is an integer of 0 to 5.

Such a specific functional cyclic compound may be prepared by condensingcyclopentadiene with a functional group-containing unsaturated compoundby the Diels-Alder reaction.

As specific examples of the specific functional cyclic compound, may bementioned:

5,6-dimethyl-5,6-dicarboxy-bicyclo[2.2.1]-2-heptene,

5,6-diethyl-5,6-dicarboxy-bicyclo[2.2.1]-2-heptene,

5,6-dimethyl-5,6-bis(carboxymethyl)-bicyclo-[2.2.1]-2-heptene,

5,6-diethyl-5,6-bis(carboxymethyl)-bicyclo-[2.2.1]-2-heptene,

5-methyl-5-carboxy-bicyclo[2.2.1]-2-heptene,

5-ethyl-5-carboxy-bicyclo[2.2.1]-2-heptene,

5-carboxy-5-carboxymethyl-bicyclo[2.2.1]-2-heptene,

5-methyl-5-carboxymethyl-bicyclo[2.2.1]-2-heptene,

5-ethyl-5-carboxymethyl-bicyclo[2.2.1]-2-heptene,

8,9-dimethyl-8,9-dicarboxy-tetracyclo-[4.4.0.1^(2,5).1^(7,10)]-3-dodecene,

8,9-diethyl-8,9-dicarboxy-tetracyclo-[4.4.0.1^(2,5).1^(7,10)]-3-dodecene,

8-methyl-8-carboxy-tetracyclo[4.4.0.1^(2,5).1^(7,10)]-3-dodecene, and

8-ethyl-8-carboxy-tetracyclo[4.4.0.1^(2,5).1^(7,10)]-3-dodecene.

The proportion of the functional group-containing unsaturated monomerused is preferably 0.01 to 5 mol %, more preferably 0.01 to 4 mol basedon the whole monomer component.

If the proportion of the functional group-containing unsaturated monomerused is lower than 0.01 mol %, the crosslink density of the resultingolefin thermoplastic elastomer becomes low, and the mechanical strengthand heat resistance thereof are liable to be lower. If the proportion ofthe functional group-containing unsaturated monomer used exceeds 5 mol %on the other hand, the crosslink density of the resulting olefinthermoplastic elastomer becomes too high, and so such an elastomerbecomes too high in hardness and brittle. It is hence not preferable touse the functional group-containing unsaturated monomer in such a low orhigh proportion. In the specific functional group-containing copolymer,a non-conjugated diene may be used as an optional monomer component inaddition to the above-described essential monomer components.

As specific examples of the non-conjugated diene, may be mentionedlinear acyclic dienes such as 1,4-hexadiene, 1,6-hexadiene and1,5-hexadiene, branched-chain acyclic dienes such as5-methyl-1,4-hexadiene, 3,7-dimethyl-1,6-octadiene,5,7-dimethyl-1,6-octadiene, 3,7-dimethyl-1,7-octadiene,7-methyl-1,6-octadiene and dihydromyrcene, and alicyclic dienes such astetrahydroindene, methyl-tetrahydroindene, dicyclopentadiene,bicyclo[2.2.1]-hept-2,5-diene, 5-methylene-2-norbornene,5-ethylidene-2-norbornene, 5-propenyl-2-norbornene,5-isopropylidene-2-norbornene, 5-cyclohexylidene-2-norbornene and5-vinyl-2-norbornene. These compounds may be used either alone or in anycombination thereof.

As preferred compounds among the above-mentioned non-conjugated dienes,may be mentioned 1,4-hexadiene, dicyclopentadiene and5-ethylidene-2-norbornene.

The proportion of the non-conjugated diene used is preferably 0 to 10mol % based on the whole monomer component. If the proportion of thenon-conjugated diene used exceeds 10 mol %, the durability of theresulting elastomer may become low in some cases.

The weight average molecular weight Mw of the specific functionalgroup-containing copolymer is generally 1,000 to 3,000,000, preferably3,000 to 1,000,000, more preferably 5,000 to 700,000 in terms ofpolystyrene as measured by gel permeation chromatography (GPC).

The specific functional group-containing copolymer preferably has a meltflow rate (MFR) of 0.01 to 100 g/10 min, more preferably 0.05 to 50 g/10min as measured under conditions of a temperature of 230° C. and a loadof 10 kg.

Further, the specific functional group-containing copolymer preferablyhas a glass transition temperature of −90 to 50° C., particularly −70 to10° C.

The specific functional group-containing copolymer may be anoil-extended polymer obtained by adding a softening agent uponpolymerization.

[Metal Ions]

The metal ions used in the present invention serve to form a crosslinkedstructure between molecules of the specific functional group-containingcopolymer by ionically bonding to the functional groups in the specificfunctional group-containing copolymer. As examples of such ions, may bementioned ions of metals of Groups I to VIII in the periodic table, suchas lithium, potassium, sodium, aluminum, magnesium, calcium, barium,cesium, strontium, rubidium, titanium, zinc, copper, iron, tin and lead.Among these, are preferred metal ions of potassium, sodium, aluminum,magnesium, barium, zinc, iron, calcium, titanium and lead.

The olefin thermoplastic elastomer according to the present inventioncan be produced in the following manner.

The specific functional group-containing copolymer is first prepared bycopolymerizing ethylene, the specific α-olefin and the functionalgroup-containing unsaturated monomer, and optionally the non-conjugateddiene.

No particular limitation is imposed on the specific preparation processof the specific functional group-containing copolymer. However, theprocess described in Japanese Patent Publication Laid Open No.2001-247629 may be suitably used.

The specific functional group-containing copolymer (hereinafter alsoreferred to as “Component (A)”) is then mixed with a metal compound(hereinafter also referred to as “Component (B)”) for supplying themetal ions for crosslinking this copolymer under suitable conditionscapable of forming a crosslinked structure, whereby the olefinthermoplastic elastomer according to the present invention is obtained.

As the metal compound making up Component (B), may be used a metaloxide, metal hydroxide, metal salt, a metal complex or the like.

As specific examples of the metal oxide used as Component (B), may bementioned CuO, MgO, BaO, ZnO, Al₂O₃, Fe₂O₃, SnO, CaO and TiO₂.

As specific examples of the metal hydroxide used as Component (B), maybe mentioned LiOH, NaOH, KOH, Cu(OH)₂, Cu₂O(OH)₂, Mg(OH)₂, Mg₂O(OH)₂,Ba(OH)₂, Zn(OH)₂, Sn(OH)₂ and Ca(OH)₂.

These metal compounds may be those treated with a silane coupling agentor higher fatty acid for the purpose of improving its dispersibility inthe specific functional group-containing copolymer which is Component(A).

These metal compounds may be used either alone or in any combinationthereof.

The proportion of the metal compound used as Component (B) is generally0.1 to 20 parts by weight, preferably 0.2 to 15 parts by weight,particularly 0.5 to 5 parts by weight per 100 parts by weight of thespecific functional group-containing copolymer as Component (A). If thisproportion is lower than 0.1 parts by weight, the crosslink density ofthe resulting olefin thermoplastic elastomer becomes low, and themechanical strength and heat resistance thereof are liable to be lower.If this proportion exceeds 20 parts by weight on the other hand, thecrosslink density of the resulting olefin thermoplastic elastomerbecomes too high, and so such an elastomer becomes too high in hardnessand brittle. It is hence not preferable to use the metal compound insuch a low or high proportion.

A metal salt of a carboxylic acid may be added as an activator inaddition to the metal compound used as Component (B) for the purpose ofimproving the miscibility of the metal compound with the specificfunctional group-containing copolymer and the heat resistance of theresulting olefin thermoplastic elastomer.

As the metal salt of the carboxylic acid, is preferably used a metalsalt of a mono-carboxylic acid, and further, the carboxylic acid is morepreferably that having 3 to 23 carbon atoms. Specific examples of thecarboxylic acid include propionic acid, acrylic acid, butyric acid,methacrylic acid, valeric acid, hexanoic acid, octanoic acid,2-ethylhexanoic acid, decanoic acid, palmitic acid, myristic acid,lauric acid, stearic acid, oleic acid, behenic acid, naphthenic acid andbenzoic acid.

A metal component in the metal salt used as the activator may beselected for use from the metal components exemplified as the metal ionsmaking up the olefin thermoplastic elastomer. It is however preferred touse a metal salt containing the same metal component as the metalcomponent in the metal compound used as Component (B).

The proportion of the metal salt used as the activator is generally 0.3to 20 parts by weight, preferably 1 to 15 parts by weight per 100 partsby weight of the specific functional group-containing copolymer asComponent (A). If this proportion is lower than 0.3 parts by weight, theeffect by use of the activator cannot be sufficiently attained. If thisproportion exceeds 20 parts by weight on the other hand, the oilresistance and mechanical strength of the resulting olefin thermoplasticelastomer may be markedly lowered in some cases.

As methods for mixing Component (A), Component (B) and the activatorused as needed with each other, may be used various methods such as amethod in which solutions or dispersions of the respective componentsare prepared, and these solutions or dispersions are mixed with eachother, and a method in which a melt kneader generally used is used.However, a method in which mixing is conducted under heating ispreferred in that an olefin thermoplastic elastomer having stableproperties is obtained. As examples, may be mentioned the followingmethods (I) and (II):

(I) A method in which a solution of the specific functionalgroup-containing copolymer as Component (A) dissolved in a propersolvent is mixed under heating with a solution or dispersion of themetal compound as Component (B) and the activator used as neededdissolved or dispersed in a proper solvent, and the solvent(s) areremoved from the resultant liquid mixture.

(II) A method in which the specific functional group-containingcopolymer as Component (A), the metal compound as Component (B) and theactivator used as needed are mixed with one another, and the resultantmixture is subjected to a dynamic heat treatment.

No particular limitation is imposed on the solvents used in the method(I). As such solvents, may be preferably used, for example, aliphatichydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons and halidesthereof in that the specific functional group-containing copolymer iseasily dissolved. As specific examples thereof, may be mentioned butane,pentane, hexane, heptane, 2-butene, 2-methyl-2-butene, cyclopentane,methylcyclopentane, cyclohexane, isooctane, benzene, toluene, xylene,chlorobenzene, dichloromethane and dichloroethane.

When the solubility of Component (B) and the activator used in thesolvent mentioned as above is low, a dispersion of Component (B) and theactivator dispersed in a suspended state in the solvent may be prepared,or any other solvent than the above solvents or additive may be addedfor dissolving Component (B) and the activator.

The proportion of the specific functional group-containing copolymer inthe solution is preferably 0.1 to 60% by weight, more preferably 0.2 to50% by weight.

The proportion of Component (B) and the activator in the solution ordispersion is preferably 0.01 to 60% by weight, more preferably 0.05 to50% by weight in total of both.

The mixing of the solutions or the solution and the dispersion may beconducted by means of a solution stirring device generally used, and thetemperature upon the mixing is preferably at least 20° C., morepreferably at least 30° C.

Upon the mixing of the solutions or the solution and the dispersion, asuitable catalyst may be added for the purpose of accelerating acrosslinking reaction with the metal.

The olefin thermoplastic elastomer according to the present invention isobtained by removing the solvent(s) from the liquid mixture obtained inthe above-described manner by a well-known method such as heating,pressure reduction or steam distillation. The olefin thermoplasticelastomer according to the present invention may also be obtained as afilm by casting the liquid mixture on a suitable base and then removingthe solvent(s).

The term “dynamic heat treatment” in the method (II) means a treatmentthat both of a shearing force-applying treatment and a heat treatmentare conducted. Such dynamic heat treatment may be conducted by means of,for example, a melt kneader. The melt kneader may be any of the batchtype and the continuous type. As specific examples of the melt kneader,may be mentioned batch type melt kneaders such as an open type mixingroll, and non-open type Banbury mixer and kneader, and continuous typemelt kneaders such as single-screw extruder, a same-direction rotatingtype continuous twin-screw extruder and an opposite-direction rotatingtype continuous twin-screw extruder.

As specific methods, may be mentioned the following methods (II-1) and(II-2):

(II-1) A mixture containing the specific functional group-containingcopolymer as Component (A), the metal compound as Component (B) andactivator used as needed is continuously subjected to a dynamic heattreatment with exothermic heat by shearing by means of a twin-screwextruder, thereby obtaining the olefin thermoplastic elastomer accordingto the present invention.

(II-2) A mixture containing the specific functional group-containingcopolymer as Component (A), the metal compound as Component (B) andactivator used as needed is subjected to a dynamic heat treatment withexothermic heat by shearing by means of a batch type kneader, therebyobtaining the olefin thermoplastic elastomer according to the presentinvention.

The conditions in the dynamic heat treatment varies according to themelting point of the specific functional group-containing copolymer usedas Component (A), the kinds of the metal compound used as Component (B),the kind of the melt kneader and the like. However, the treatmenttemperature is 120 to 350° C., preferably 150 to 290° C., and thetreatment time is 20 seconds to 320 minutes, preferably 30 seconds to 25minutes. The shearing force applied to the mixture is 10 to 2,000/sec,preferably 100 to 1000/sec in terms of a shear rate.

Since the olefin thermoplastic elastomer according to the presentinvention obtained in such a manner has a melt flow rate (MFR) of atleast 0.5 g/10 min, preferably at least 1 g/10 min as measured underconditions of a temperature of 230° C. and a load of 10 kg and apermanent set of at most 30%, preferably at most 20%, it has the same orsimilar rubber elasticity and molding or forming and processability asthose of the conventional olefin thermoplastic elastomers, and moreoverhas good flexibility, mechanical strength and wear resistance and isexcellent in scratch resistance in particular as apparent from Exampleswhich will be described subsequently.

[Olefin Thermoplastic Elastomer Composition]

The olefin thermoplastic elastomer according to the present inventioncan be used as an olefin thermoplastic elastomer composition by mixingit with a polymeric compound (hereinafter also referred to as “Component(C)”) selected from a thermoplastic resin and rubber.

As the thermoplastic resin and rubber used as Component (C), variousresins and rubbers may be used without particular limitation so far asthey are those other than the specific functional group-containingcopolymer, and specific examples thereof include polyethylene and maleicanhydride-grafted polymers thereof, polyisobutylene, ethylene.vinylacetate copolymers, ethylene acrylate, ethylene.acrylic acid copolymers,polypropylene and maleic anhydride-grafted polymers thereof,polyisobutylene, chlorinated polypropylene, 4-methyl-1-pentene resins,polystyrene, ABS resins, AS resins, acrylic resins, methacrylic resins,vinyl chloride resins, vinylidene chloride resins, polyamide resins,polycarbonates, ethylene.α-olefin copolymer rubber and maleicanhydride-grafted polymers thereof, ethylene.α-olefin-non-conjugateddiene copolymer rubber, styrene.butadiene rubber and hydrogenatedproducts thereof, maleic anhydride-grafted polymers of hydrogenatedproducts of styrene.butadiene rubber, butadiene rubber and hydrogenatedproducts thereof, maleic anhydride-grafted polymers of hydrogenatedproducts of butadiene rubber, isoprene rubber and hydrogenated productsthereof, maleic anhydride-grafted polymers of hydrogenated products ofisoprene rubber, styrene.isoprene rubber and hydrogenated productsthereof, maleic anhydride-grafted polymers of hydrogenated products ofstyrene.isoprene rubber, nitrile rubber and hydrogenated productsthereof, acrylic rubber, silicone rubber, fluorocarbonrubber, butylrubber, and natural rubber. Polyethylene and polypropylene areparticularly preferred. These polymeric compounds may be used asComponent (C) either alone or in any combination thereof.

The proportion of the polymeric compound used as Component (C) is atmost 300 parts by weight, preferably 1 to 200 parts by weight per 100parts by weight of the specific functional group-containing copolymermaking up the olefin thermoplastic elastomer.

The olefin thermoplastic elastomer according to the present inventioncan be used as an olefin thermoplastic elastomer composition by adding asoftening agent (hereinafter also referred to as “Component (D)”)thereto.

The softening agent used as Component (D) may be either added to amonomer solution for obtaining the specific functional group-containingcopolymer making up the olefin thermoplastic elastomer or added upon theproduction of the olefin thermoplastic elastomer or after the productionthereof.

No particular limitation is imposed on the softening agent used asComponent (D) so far as it is a softening agent for rubber generallyused, and examples thereof include paraffinic, naphthenic and aromaticmineral oil type hydrocarbons and low-molecular weight hydrocarbons ofthe polybutene and polybutadiene types, and the like. Among these,mineral oil type hydrocarbons are preferred, and those having a weightaverage molecular weight of 300 to 2000, particularly 500 to 1500 arepreferred.

The softening agent for rubber composed of mineral oil type hydrocarbonsis generally a mixture of three of aromatic hydrocarbons, naphthenichydrocarbons and paraffinic hydrocarbons, and those that the number ofcarbon atoms belonging to paraffinic hydrocarbons is at least 50% of thewhole number of carbon atoms, those that the number of carbon atomsbelonging to naphthenic hydrocarbons is 30 to 45% of the whole number ofcarbon atoms, and those that the number of carbon atoms belonging toaromatic hydrocarbons is at least 30% of the whole number of carbonatoms are classified as paraffin type oil, naphthenic type oil andaromatic type oil, respectively. In the present invention, paraffin typeoil is preferred, with hydrogenated paraffin type oil being particularlypreferred. The mineral oil type hydrocarbons preferably have a kinematicviscosity of 20 to 800 cSt, particularly 50 to 600 cSt at 40° C. and apour point of −40 to 0° C., particularly −30 to 0° C.

The proportion of the softening agent used as Component (D) is at most100 parts by weight, preferably 1 to 67 parts by weight per 100 parts byweight of the specific functional group-containing copolymer making upthe olefin thermoplastic elastomer.

The olefin thermoplastic elastomer composition according to the presentinvention may be produced by adding the polymeric compound as Component(C) and/or the softening agent as Component (D) to the olefinthermoplastic elastomer and heating and mixing them. However, aspreferred preparation methods, may be mentioned the following methods(III) and (IV):

(III) A method in which a solution of the specific functionalgroup-containing copolymer as Component (A) dissolved in a propersolvent is mixed under heating with a solution or dispersion of themetal compound as Component (B) and the activator used as neededdissolved or dispersed in a proper solvent and a solution or dispersionof the polymeric compound as Component (C) and/or the softening agent asComponent (D) dissolved or dispersed in a proper solvent, and thesolvent(s) are removed from the resultant liquid mixture.

No particular limitation is imposed on the solvents used in this method.It is however preferred to use, for example, aliphatic hydrocarbons,alicyclic hydrocarbons, aromatic hydrocarbon and halides thereof in thatthe specific functional group-containing copolymer is easily dissolved.As specific examples thereof, may be mentioned butane, pentane, hexane,heptane, 2-butene, 2-methyl-2-butene, cyclopentane, methylcyclopentane,cyclohexane, isooctane, benzene, toluene, xylene, chlorobenzene,dichloromethane and dichloroethane.

When the solubility of Component (B) and the activator used in the abovesolvent is low, a dispersion of Component (B) and the activatordispersed in a suspended state in the solvent may be prepared, or anyother solvent or additive than the above solvents may be added fordissolving Component (B) and the activator.

When the solubility of Component (C) and Component (D) in the abovesolvent is low, they may be dispersed in a suspended state in thesolvent, any other solvent than the above solvents or additive may beadded for dissolving Component (C) and Component (D), or Component (C)and Component (D) may be added after removing the solvent(s), and theresultant mixture may be subjected to the dynamic heat treatment.

The mixing of the solutions or the solution and the dispersion(s) may beconducted by means of a solution stirring device generally used, and thetemperature upon the mixing is preferably at least 20° C., morepreferably at least 30° C.

Upon the mixing of the solutions or the solution and the dispersion(s),a suitable catalyst may be added for the purpose of accelerating acrosslinking reaction with the metal.

The olefin thermoplastic elastomer composition according to the presentinvention is obtained by removing the solvent(s) from the liquid mixtureobtained in the above-described manner by a well-known method such asheating, pressure reduction or steam distillation. The olefinthermoplastic elastomer composition according to the present inventionmay also be obtained as a film by casting the liquid mixture on asuitable base and then removing the solvent(s). (IV) A method in whichthe specific functional group-containing copolymer as Component (A), themetal compound as Component (B), the activator used as needed, and thepolymeric compound as Component (C) and/or the softening agent asComponent (D) are mixed with one another, and the resultant mixture issubjected to a dynamic heat treatment.

The conditions for the dynamic heat treatment in this method variesaccording to the melting point of the specific functionalgroup-containing copolymer used as Component (A), the kind of the metalcompound used as Component (B), the melting point of the polymericcompound used as Component (C), the kind of the melt kneader, and thelike. However, the treatment temperature is 120 to 350° C., preferably150 to 290° C., and the treatment time is 20 seconds to 320 minutes,preferably 30 seconds to 25 minutes. The shearing force applied to themixture is 10 to 2,000 s⁻¹, preferably 100 to 1000 s⁻¹ in terms of ashear rate.

Since the olefin thermoplastic elastomer composition according to thepresent invention obtained in such a manner has a melt flow rate (MFR)of at least 0.5 g/10 min, preferably at least 1 g/10 min as measuredunder conditions of a temperature of 230° C. and a load of 10 kg, apermanent set of at most 30%, preferably at most 20% and a durometer Ahardness of at most 96, preferably at most 90, it has the same orsimilar rubber elasticity, flexibility and molding or forming andprocessability as those of the conventional olefin thermoplasticelastomer compositions, and moreover has good mechanical strength andwear resistance and is excellent in scratch resistance in particular asapparent from Examples which will be described subsequently.

Into the olefin thermoplastic elastomer composition according to thepresent invention, may be incorporated for use various kinds ofadditives as needed, for example, lubricants, stabilizers such asantioxidants, heat stabilizers, weathering agents, metal inactivators,ultraviolet absorbents, light stabilizers and copper inhibitors,antiseptic and mildewproofing agents, dispersing agents, plasticizers,nucleating agents, flame retardants, tackifiers, foaming aids, colorantssuch as titanium oxide and carbon black, fillers such as powders ofmetals such as ferrite, inorganic fibers such as glass fibers and metalfibers, organic fibers such as carbon fibers and aramide fibers,composite fibers, inorganic whiskers such as potassium titanate whisker,glass beads, glass balloons, glass flakes, asbestos, mica, calciumcarbonate, talc, silica, calcium silicate, hydrotalcite, kaolin,diatomaceous earth, graphite, pumice, ebonite powder, cotton flock, corkpowder, barium sulfate, fluorocarbonresins and polymer beads, ormixtures thereof, fillers such as polyolefin waxes, cellulose powder,rubber powder and wood powder, and low-molecular weight polymers.

The olefin thermoplastic elastomers and their compositions according tothe present invention may be easily processed by melt molding or formingsuch as injection molding, extrusion, blow molding, compression molding,vacuum forming, laminate molding or calendering because the specificfunctional group-containing copolymer therein is crosslinked with metalions, whereby molded or formed thermoplastic elastomer productsexcellent in rubber elasticity, flexibility and mechanical propertiescan be provided.

The molded or formed products composed of the olefin thermoplasticelastomers and their compositions according to the present invention mayalso be used by bonding to or multi-layer laminating on ordinary moldedor formed olefin vulcanized rubber products or ordinary molded or formedolefin thermoplastic elastomer products.

Since the olefin thermoplastic elastomers and their compositionsaccording to the present invention have excellent rubber elasticity,flexibility, molding or forming and processability and scratchresistance, they can be widely used as interior or exterior surfacematerials for automotive bumpers, exterior trims, window sealinggaskets, door sealing gaskets, gaskets for trunk room, roof side rails,emblems, inner panels, door trims and console boxes, weatherstrips andthe like, leather sheets of which scratch resistance is required,sealing materials, interior or exterior surface materials and the likefor aircrafts and marine vessels, sealing materials, interior orexterior surface materials, waterproofing sheet materials and the likefor civil engineering and construction, sealing materials and the likefor general machines and apparatus, packings, skins, housings and thelike for light electric parts, rolls and cleaning blades for informationinstruments, films and sealing materials for electronic parts,protecting films for images such as photographs, decorative films forbuilding materials, medical instrument parts, electric wires, dailyneeds and sports goods as the general processed products in which theconventional olefin thermoplastic elastomers are in use.

The present invention will hereinafter be described specifically by thefollowing examples. However, the present invention is not limited bythese examples.

Various components used in the following examples and comparativeexamples are as follows:

[Olefin Random Copolymer]

(1) Specific Functional Group-Containing Copolymer (A-1):

A specific functional group-containing copolymer in which the content ofthe structural unit derived from ethylene is 77.4 mol %, the content ofthe structural unit derived from propylene is 21.8 mol %, the content ofthe structural unit derived from 5-ethylidene-2-norbornene is 0 mol %,and the content of the structural unit derived from5-methyl-5-carboxy-bicyclo-[2.2.1]-2-heptene is 0.8 mol %, and theweight average molecular weight (Mw) is 13.1×10⁴.

(2) Specific Functional Group-Containing Copolymer (A-2):

A specific functional group-containing copolymer in which the content ofthe structural unit derived from ethylene is 75.8 mol %, the content ofthe structural unit derived from propylene is 22.4 mol %, the content ofthe structural unit derived from 5-ethylidene-2-norbornene is 1.2 mol %,and the content of the structural unit derived from5-methyl-5-carboxy-bicyclo-[2.2.1]-2-heptene is 0.6 mol %, and theweight average molecular weight (Mw) is 18.6×10⁴.

(3) Specific Functional Group-Containing Copolymer (A-3):

A specific functional group-containing copolymer in which the content ofthe structural unit derived from ethylene is 86.1 mol %, the content ofthe structural unit derived from propylene is 10.6 mol %, the content ofthe structural unit derived from 5-ethylidene-2-norbornene is 2.6 mol %,and the content of the structural unit derived from5-methyl-5-carboxy-bicyclo-[2.2.1]-2-heptene is 0.7 mol %, and theweight average molecular weight (Mw) is 16.5×10⁴.

(4) Olefin Copolymer (H-1):

An olefin random copolymer (product of JSR Corporation; trade name“EP57P”) in which the content of the structural unit derived fromethylene is 76.1 mol %, the content of the structural unit derived frompropylene is 22.7 mol %, and the content of the structural unit derivedfrom 5-ethylidene-2-norbornene is 1.2 mol %, and the Mooney viscosity(ML₁₊₄, 100° C.) is 88.

(5) Maleic Anhydride-Modified Copolymer (H-2):

A maleic anhydride-modified olefin random copolymer (product of JSRCorporation; trade name “T7761P”) in which the content of the structuralunit derived from ethylene is 80.4 mol %, the content of the structuralunit derived from propylene is 19.3 mol %, and the content of thestructural unit derived from 5-ethylidene-2-norbornene is 0 mol %, theamount of acid addition is 0.3 mol %, and the Mooney viscosity (ML₁₊₄,100° C.) is 63.

[Metallic Compound]

(1) Metal Compound (B-1):

Magnesium hydroxide (product of Kyowa Chemicals Co., Ltd.; trade name“Kisuma 5A”) surface-treated with a higher fatty acid.

(2) Metal Compound (B-2):

Magnesium hydroxide (product of Kyowa Chemicals Co., Ltd.; trade name“Kisuma 5NH”) surface-treated with a silane coupling agent.

(3) Metal Compound (B-3):

Zinc oxide (zinc white).

[Polymeric Compound]

(1) Polyethylene Resin (C-1):

A linear, low-density polyethylene resin (product of Japan Polychem Co.,Ltd.; trade name “Novatec LLDPE UF423”) having an MFR (measured at atemperature of 190° C. and a load of 2.16 kg) of 0.8 g/10 min.

(2) Polypropylene Resin (C-2):

A propylene resin (product of Japan Polychem Co., Ltd.; trade name“Novatec PP MA4”) having an MFR (measured at a temperature of 230° C.and a load of 2.16 kg) of 5 g/10 min.

(3) Rubber (C-3)

Ethylene-propylene copolymer rubber (ethylene content=78.6 mol %,propylene content=21.4 mol %, 5-ethylidene-2-norbornene content=0 mol %;the Mooney viscosity (ML₁₊₄, 100° C.)=25; product of JSR Corporation;trade name “EP02P”).

[Softening Agent]

Softening agent (D-1):

Hydrogenated paraffinic mineral oil (product of Idemitsu Kosan Co.,Ltd.; trade name “Dyana Process Oil PW380”).

[Other Additives]

Activator (I-1): Magnesium stearate.

Activator (I-2): Zinc stearate.

Organic Peroxide (K-1): 2,5-Dimethyl-2,5-di(tert-butylperoxy)hexane(product of Nippon Oil & Fats Co., Ltd.; trade name “Perhexa 25B40”).

Crosslinking Aid (L-1): Divinylbenzene (product of Sankyo ChemicalIndustries, Ltd.) having a purity of 55%.

Antioxidant (M-1):2-[1-(2-Hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenylacrylate (product of Sumitomo Chemical Co., Ltd.; trade name “SumilizerGS”).

Antioxidant (M-2): Bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritoldiphosphite (product of Asahi Denka Co. Ltd; trade name “AdekastabPEP-36”).

EXAMPLE 1

A 10-L double arm type pressurizing kneader (manufactured by MoriyamaCompany, Ltd.) heated to 230° C. was charged with 100 parts by weight ofthe specific functional group-containing copolymer (A-1), 1 part byweight of the metal compound (B-1) and 4.5 parts by weight of theactivator (I-1), and the contents were kneaded (at a shear rate of 200s⁻¹) for 20 minutes at 40 rpm. The resultant bulk kneaded product inmolten state was then pelletized by a feeder extruder (manufactured byMoriyama Company, Ltd.) set at 180° C. and 40 rpm to obtain an olefinthermoplastic elastomer.

The thus-obtained pellets of the olefin thermoplastic elastomer weresubjected to press molding under conditions of a mold temperature of180° C., a pressurizing and heating time of 10 minutes and pressurizingand cooling time of 5 minutes by means of an electrically heatedpressurizing press molding machine (manufactured by Kansai Roll K.K.),thereby obtaining a molded sheet having a size of 12 cm×12 cm×0.2 cm.

[Evaluation of Olefin Thermoplastic Elastomer]

With respect to the olefin thermoplastic elastomer thus obtained, itsmelt flow rate (MFR) was measured as an index of flowability underconditions of a temperature of 230° C. and a load of 10 kg. The resultis shown in the following Table 1.

The resultant molded sheet of the olefin thermoplastic elastomer wasused to determine a durometer A hardness as an index of flexibility, apermanent set as an index of rubber elasticity, tensile strength atbreak and tensile elongation at break as mechanical strength, wearresistance, and a specific gravity in accordance with the followingrespective methods, and moreover conduct Scratch Resistance Test 1 andScratch Resistance Test 2. The results are shown in Table 1.

(1) Durometer A hardness: Measured in accordance with JIS-K 6253.

(2) Permanent set: Measured in accordance with JIS-K 6262.

(3) Tensile strength at break and tensile elongation at break: Measuredin accordance with JIS-K 6251.

(4) Wear resistance: A DIN abrasion test was performed in accordancewith JIS-K 6264 to determine a wear resistance factor.

(5) Specific gravity: Measured in accordance with JIS-K 7112.

(6) Scratch Resistance Test 1: A T-bar scratch tester manufactured byToyo Seiki Seisaku-sho, Ltd. was used to scan a metal claw loaded with10 g on the surface of the molded sheet. This process was repeated untilthe surface of the molded sheet was marred with the load being increased10 g by 10 g. A value of the load at the time the surface of the moldedsheet was first marred was recorded. In this test, the greater the valueof the load recorded, the better the scratch resistance.

(7) Scratch Resistance Test 2:

The surface of the molded sheet was rubbed with a thumb nail to visuallyjudge the degree of marring on the surface in accordance with thefollowing standard:

1: The surface was not marred at all;

2: The surface was slightly marred, but immediately restored to becomemarring-free;

3: The surface was slightly marred;

4: The surface was deeply marred.

COMPARATIVE EXAMPLE 1

The specific functional group-containing copolymer (A-1) was subjectedto press molding in the same manner as in Example 1, thereby producing amolded sheet to evaluate it. The results are shown in Table 2.

EXAMPLES 2 TO 6 AND 8 TO 12, AND COMPARATIVE EXAMPLES 2 AND 3

A 10-L double arm type pressurizing kneader (manufactured by MoriyamaCompany, Ltd.) heated to 230° C. was charged with respective componentsin accordance with their corresponding formulations shown in Tables 1and 2, and the respective contents were kneaded for 20 minutes at 40rpm. Each of the resultant bulk kneaded products in a molten state wasthen pelletized by a feeder extruder (manufactured by Moriyama Company,Ltd.) set at 180° C. and 40 rpm to obtain an olefin thermoplasticelastomer or olefin thermoplastic elastomer composition.

The thus-obtained pellets of the olefin thermoplastic elastomer orolefin thermoplastic elastomer composition were subjected to pressmolding in the same manner as in Example 1, whereby a molded sheet wasproduced to evaluate it. The results are shown in Tables 1 and 2.

EXAMPLE 7

A solution of the specific functional group-containing copolymer (A-3)dissolved in xylene so as to give the copolymer concentration of 5% byweight was prepared, and a suspension of the metal compound (B-2) andthe activator (I-1) finely dispersed in xylene so as to giveconcentrations of 1.0% by weight and 4.5% by weight, respectively, wasprepared. The solution and the suspension were mixed with each other soas to give the mixing proportions of the specific functionalgroup-containing copolymer (A-3), metal compound (B-2) and activator(I-1) shown in Table 1. While stirring the resultant liquid, it washeated at 130° C. for 30 minutes. The resultant liquid mixture was thensubjected to a heat treatment under reduced pressure to remove xylene,thereby obtaining an olefin thermoplastic elastomer. The resultantolefin thermoplastic elastomer thus obtained was chopped and thensubjected to press molding in the same manner as in Example 1, whereby amolded sheet was produced to evaluate it. The results are shown in Table1.

EXAMPLE 13

A 10-L double arm type pressurizing kneader (manufactured by MoriyamaCompany, Ltd.) heated to 230° C. was charged with the specificfunctional group-containing copolymer (A-3) and the polyethylene resin(C-1) in a proportion of 100:11.1 in terms of a weight ratio, and thecontents were kneaded for 20 minutes at 40 rpm. The resultant bulkkneaded product in a molten state was then pelletized by a feederextruder (manufactured by Moriyama Company, Ltd.) set at 180° C. and 40rpm to obtain a copolymer composition.

To 111.1 parts by weight of the thus-obtained pellets of the copolymercomposition, were added 1.1 parts by weight of the metal compound (B-2)and 5.0 parts by weight of the activator (I-1), and the components weremixed for 30 seconds by means of a Henschel mixer. The resultant mixturewas then extruded by means of a twin-extruder (Model “PCM-45”manufactured by Ikegai Ltd.; same-direction completely intermeshingscrews; L/D, a rate of the length L of a screw flight portion to thediameter D of each screw: 33.5) while conducting a dynamic heattreatment under conditions that the mixture was retained for 2 minutesat 210° C. and 300 rpm (shear rate: 900 s⁻¹), thereby obtaining pelletsof the olefin thermoplastic elastomer composition.

The resultant pellets of the olefin thermoplastic elastomer compositionwere subjected to press molding in the same manner as in Example 1,whereby a molded sheet was produced to evaluate it. The results areshown in Table 2.

COMPARATIVE EXAMPLE 4

A 10-L double arm type pressurizing kneader (manufactured by MoriyamaCompany, Ltd.) heated to 230° C. was charged with the maleicanhydride-modified copolymer (H-2), the polypropylene resin (C-2) andthe softening agent (D-1) in a proportion of 100:33.9:35.6 in terms of aweight ratio, and the contents were kneaded for 20 minutes at 40 rpm.The resultant bulk kneaded product in a molten state was then pelletizedby a feeder extruder (manufactured by Moriyama Company, Ltd.) set at180° C. and 40 rpm to obtain a copolymer composition.

To 169.5 parts by weight of the thus-obtained pellets of the copolymercomposition, were added 1.7 parts by weight of the organic peroxide(K-1) and 2.1 parts by weight of the crosslinking aid (L-1), and theircomponents were mixed for 30 seconds by means of a Henschel mixer. Theresultant mixture was then extruded by means of a twin-extruder (Model“PCM-45” manufactured by Ikegai Ltd.; same-direction completelyintermeshing screws; L/D, a rate of the length L of a screw flightportion to the diameter D of each screw: 33.5) while conducting adynamic heat treatment under conditions that the mixture was retainedfor 2 minutes at 210° C. and 300 rpm (shear rate: 900 s⁻¹), therebyobtaining pellets of the olefin thermoplastic elastomer composition.

The resultant pellets of the olefin thermoplastic elastomer compositionwere subjected to press molding in the same manner as in Example 1,whereby a molded sheet was produced to evaluate it. The results areshown in Table 2.

TABLE 1 Examples 1 2 3 4 5 6 7 8 9 Formulation of components (parts byweight) Specific functional group-containing copolymer (A-1) 100 100 100— 100 — — — — Specific functional group-containing copolymer (A-2) — — —100 — — — — — Specific functional group-containing copolymer (A-3) — — —— — 100 100 100 100 Metal compound (B-1) 1.0 1.1 1.2 — — — — — — Metalcompound (B-2) — — — 1.4 — 1.0 1.0 1.1 2.0 Polyethylene resin (C-1) —11.1 — — 13.0 — — 11.1 100 Softening agent (D-1) — — 17.6 42.9 16.9 — —— — Activator (I-1) 4.5 5.0 5.3 6.4 5.8 4.5 4.5 5.0 9.0 Mixing methodKNEADER KNEADER KNEADER KNEADER KNEADER KNEADER SOLUTION KNEADER KNEADEREvaluation Results MFR (230° C., 10 kg) [g/10 min] 67 59 183 20 152 6.45.9 9.0 9.3 Durometer A hardness 71 75 63 48 68 64 66 72 95 Parmanentset [%] 7 9 8 5 10 4 3 6 18 Tensile strength at break [MPa] 4.5 4.6 3.15.4 3.1 13.7 16.2 21.0 22.5 Tensile elongation at break [%] 690 580 700940 510 800 780 810 840 Wear registance 48 51 52 50 51 34 30 35 39Specific gravity 0.891 0.895 0.893 0.893 0.895 0.898 0.898 0.902 0.916Mar Registance Test 1 100 80 80 90 80 500 550 300 110 Mar RegistanceTest 2 2 2 2 2 2 1 1 2 2

TABLE 2 Examples Comparative examples 10 11 12 13 1 2 3 4 Formulation ofcomponents (parts by weight) Specific functional group-containingcopolymer (A-1) — — — — 100 — — — Specific functional group-containingcopolymer (A-3) 100 100 100 100 — — — — Olefin copolymer (H-1) — — — — —100 — 100 Maleic anhydride-modified copolymer (H-2) — — — — — — 100 —Metal compound (B-2) 1.1 — 1.1 1.1 — 1.4 1.4 — Metal compound (B-3) —1.1 — — — — — — Polyethylene resin (C-1) — 11.1 11.1 11.1 — — — —Polypropylene resin (C-2) — — — — — — — 33.9 Rubber (C-3) 11.1 — — — — —— — Softening agent (D-1) — — — — — 42.9 42.9 35.6 Activator (I-1) 5.0 —5.0 5.0 — 6.4 6.4 — Activator (I-2) — 5.0 — — — — — — Organic peroxide(K-1) — — — — — — — 1.7 Crosslinking aid (L-1) — — — — — — — 2.1Antioxidant (M-1) — — 0.2 0.2 — — — — Antioxidant (M-2) — — 0.2 0.2 — —— — Mixing method Kneader Kneader KNEADER EXTRUDER — Kneader KneaderExtruder Evaluation Results MFR (230° C., 10 kg) [g/10 min] 9.1 5.8 9.02.7 60 8.2 Not flowed 1.0 Durometer A hardness 68 73 72 73 48 38 58 75Parmanent set [%] 5 8 5 3 136 107 9 15 Tensile strength at break [MPa]18.3 20.5 22.6 25.8 1.1 1.5 2.5 8.6 Tensile elongation at break [%] 810830 820 800 1340 1280 186 550 Wear registance 37 38 35 29 190 178 60 159Specific gravity 0.898 0.905 0.902 0.902 0.864 0.890 0.892 0.889 MarRegistance Test 1 310 310 320 350 10 10 70 10 Mar Registance Test 2 2 22 2 4 4 3 4

As apparent from the results shown in Tables 1 and 2, it is understoodthat the olefin thermoplastic elastomers or their compositions accordingto Examples 1 to 13 are excellent in all of scratch resistance,mechanical strength, rubber elasticity and wear resistance.

The sheet obtained by forming the pellets of the olefin thermoplasticelastomer composition obtained in Example 11 was very smooth in itssurface, and foreign matter attributable to crosslinked gel that iscalled “gels” was not observed.

On the contrary, in Comparative Example 1, the copolymer was notcrosslinked with any metal ions, and so it was low in mechanicalstrength, rubber elasticity, scratch resistance and wear resistance.

In Comparative Example 2, the olefin copolymer had no functional group,and so no crosslinked structure was formed even when the metal compoundwas added and the dynamic heat treatment was conducted, and thecopolymer was low in mechanical strength, rubber elasticity, scratchresistance and wear resistance.

The olefin thermoplastic elastomer composition according to ComparativeExample 3 was low in processability (flowability) and also in mechanicalstrength and scratch resistance.

The olefin thermoplastic elastomer composition according to ComparativeExample 4 had the similar rubber elasticity (permanent set), flexibility(hardness) and mechanical strength as those of the olefin thermoplasticelastomer or its composition according to Examples 1 or 2, but was lowin scratch resistance and wear resistance.

EFFECTS OF THE INVENTION

The olefin thermoplastic elastomers and their compositions according tothe present invention have the same or similar rubber elasticity,flexibility and molding or forming and processability as those of theconventional olefin thermoplastic elastomers, and moreover are good inmechanical properties and wear resistance and excellent in scratchresistance in particular, and thus can be easily processed by meltmolding or forming such as injection molding, extrusion, blow molding,compression molding, vacuum forming, laminate molding or calendering,whereby molded or formed thermoplastic elastomer products excellent inrubber elasticity, flexibility and mechanical properties can beprovided.

The molded or formed products composed of the olefin thermoplasticelastomers and their compositions according to the present invention mayalso be used by bonding to or multi-layer laminating on ordinary moldedor formed olefin vulcanized rubber products or molded or formed olefinthermoplastic elastomer products.

Since the olefin thermoplastic elastomers and their compositionsaccording to the present invention have excellent rubber elasticity,flexibility, molding and processability and scratch resistance, they canbe widely used as interior or exterior surface materials for automotivebumpers, sheathing chenille, window sealing gaskets, door sealinggaskets, gaskets for trunk room, roof side rails, emblems, inner panels,door trims and console boxes, weatherstrips and the like, leather sheetsof which scratch resistance is required, sealing materials, interior orexterior surface materials and the like for aircrafts and marinevessels, sealing materials, interior or exterior surface materials,waterproofing sheet materials and the like for civil engineering andconstruction, sealing materials and the like for general machines andapparatus, packings, skins, housings and the like for light electricparts, rolls and cleaning blades for information instruments, films andsealing materials for electronic parts, protecting films for images suchas photographs, decorative films for building materials, medicalinstrument parts, electric wires, daily needs and sports goods as thegeneral processed products in which the conventional olefinthermoplastic elastomers are in use.

According to the production processes of the present invention, theabove-described olefin thermoplastic elastomers and their compositionscan be produced with advantage.

What is claimed is:
 1. An olefin thermoplastic elastomer comprising anolefin random copolymer formed by copolymerizing ethylene, an α-olefinhaving 3 to 10 carbon atoms and an unsaturated monomer having afunctional group, and optionally a non-conjugated diene, and metal ionscrosslinking the olefin random copolymer.
 2. The olefin thermoplasticelastomer according to claim 1, wherein the functional group in theunsaturated monomer having a functional group is a carboxyl group,hydroxyl group, epoxy group or sulfonic group.
 3. The olefinthermoplastic elastomer according to claim 1, wherein the unsaturatedmonomer having a functional group is a functional cyclic compoundrepresented by the following general formula (1):

wherein R¹ represents a hydrogen atom or a hydrocarbon group having 1 to10 carbon atoms, Y¹, Y² and Y³ denote, independently of one another, ahydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms or —COOH,with the proviso that at least one of Y¹, Y² and Y³ is —COOH, and whenat least two of Y¹, Y² and Y³ are —COOH, they may be bonded to eachother to form an acid anhydride (—CO—(O)—CO—), o is an integer of 0 to2, and p is an integer of 0 to
 5. 4. The olefin thermoplastic elastomeraccording to claim 3, wherein the olefin random copolymer is formed bycopolymerizing 35 to 94.99 mol % of ethylene, 5 to 50 mol % of theα-olefin having 3 to 10 carbon atoms, 0.01 to 5 mol % of the functionalcyclic compound represented by the general formula (1) and 0 to 10 mol %of the non-conjugated diene.
 5. The olefin thermoplastic elastomeraccording to claim 1, wherein the metal ions are ions of a metalselected from the group consisting of potassium, sodium, aluminum,magnesium, barium, zinc, iron, calcium, titanium and lead.
 6. The olefinthermoplastic elastomer according to claim 1, which has a melt flow rateof at least 0.5 g/10 min as measured under conditions of a temperatureof 230° C. and a load of 10 kg, a permanent set of at most 30% and adurometer A hardness of at most
 96. 7. A process for producing an olefinthermoplastic elastomer, comprising: mixing a solution with 100 parts byweight of an olefin random copolymer formed by copolymerizing 35 to94.99 mol % of ethylene, 5 to 50 mol % of an α-olefin having 3 to 10carbon atoms, 0.01 to 5 mol % of a functional cyclic compoundrepresented by the general formula (1) set forth in claim 3 and 0 to 10mol % of a non-conjugated diene dissolved in a solvent with a liquidwith 0.1 to 20 parts by weight of a metal compound dissolved ordispersed in a solvent, at a temperature of at least 20° C.; andremoving the solvent(s), from the resultant liquid mixture.
 8. A processfor producing an olefin thermoplastic elastomer, comprising: subjecting100 parts by weight of an olefin random copolymer formed bycopolymerizing 35 to 94.99 mol % of ethylene, 5 to 50 mol % of anα-olefin having 3 to 10 carbon atoms, 0.01 to 5 mol % of a functionalcyclic compound represented by the general formula (1) set forth inclaim 3 and 0 to 10 mol % of a non-conjugated diene and 0.1 to 20 partsby weight of a metal compound to a dynamic heat treatment underconditions of a temperature of 120 to 350° C. and a shear rate of 10 to2,000 s⁻¹.
 9. An olefin thermoplastic elastomer composition, comprising:the olefin thermoplastic elastomer according to claim 1, and a polymericcompound selected from a thermoplastic resin and rubber and/or asoftening agent, wherein the polymeric compound and the softening agentare contained in proportions of at most 300 parts by weight and at most100 parts by weight, respectively, per 100 parts by weight of the olefinrandom copolymer forming the olefin thermoplastic elastomer.
 10. Theolefin thermoplastic elastomer composition according to claim 9, whichhas a melt flow rate of at least 0.5 g/10 min as measured underconditions of a temperature of 230° C. and a load of 10 kg, a permanentset of at most 30% and a durometer A hardness of at most
 96. 11. Aprocess for producing an olefin thermoplastic elastomer composition,comprising: subjecting 100 parts by weight of an olefin random copolymerformed by copolymerizing 35 to 94.99 mol % of ethylene, 5 to 50 mol % ofan α-olefin having 3 to 10 carbon atoms, 0.01 to 5 mol % of a functionalcyclic compound represented by the general formula (1) set forth inclaim 3 and 0 to 10 mol % of a non-conjugated diene, 0.1 to 20 parts byweight of a metal compound, and at most 300 parts by weight of apolymeric compound selected from a thermoplastic resin and rubber and/orat most 100 parts by weight of a softening agent to a dynamic heattreatment under conditions of a temperature of 120 to 350° C. and ashear rate of 10 to 2,000 s⁻¹.
 12. A molded or formed product formed ofthe olefin thermoplastic elastomer according to claim 1 or the olefinthermoplastic elastomer composition according to claim 9.